Without a history of trauma, the differential diagnosis of a rapidly enlarging neck mass is limited. Once an aneurysm or infectious source, such as abscess, has been ruled out, neoplasms are thought to be the main cause. Lymphoma and anaplastic thyroid carcinoma are the most common neoplasms involved, and distinguishing between them is essential.1,2Lymphoma responds to systemic treatment, while advanced anaplastic thyroid carcinoma is uniformly fatal.1A core needle biopsy provides diagnostic tissue, avoiding the potential morbidity of open procedures. Unlike fine-needle aspiration biopsy specimens, core specimens provide sufficient tissue for flow cytometry, immunohistochemical studies, and electron microscopy, which may be necessary for distinguishing between poorly differentiated malignant tumors.
Radiology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2008;134(4):444. doi:10.1001/archotol.134.4.444